I. Field
The present disclosure relates generally to communication, and more specifically to transmission techniques for a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
A multiple-access system may utilize one or more multiplexing schemes such as code division multiplexing (CDM), time division multiplexing (TDM), etc. The system may be deployed and may serve existing terminals. It may be desirable to improve the performance of the system while retaining backward compatibility for the existing terminals. For example, it may be desirable to employ spatial techniques such as multiple-input multiple-output (MIMO) and spatial division multiple access (SDMA) to improve throughput and/or reliability by exploiting additional spatial dimensionalities provided by use of multiple antennas.
There is therefore a need in the art for transmission techniques that can support advanced communication techniques (e.g., spatial techniques) while retaining backward compatibility for existing terminals.